Keloid and Hypertrophic Scars
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Direct answer
Keloids are dermal fibroproliferative scars that extend beyond the original wound margin and rarely regress without treatment, whereas hypertrophic scars remain confined to the wound and tend to flatten over time. Risk is highest in people with darker skin, younger age and a family history, with sternum, shoulders and earlobes as common sites. Silicone, pressure and intralesional steroids are first-line, and excision alone carries a high recurrence rate.
What you must remember
- Definition: a keloid grows beyond the original incision or injury, whereas a hypertrophic scar stays within its boundaries.
- Regression: hypertrophic scars often flatten over months to a year or two; keloids usually persist and do not regress spontaneously.
- Histology: keloids show thick, hyalinised collagen bundles arranged haphazardly, with increased fibroblasts; hypertrophic scars are more orderly.
- Risk factors: darker skin types (Fitzpatrick IV to VI), younger age with a peak between 10 and 30 years, and a family history of keloids.
- High-risk sites: sternum, shoulders, upper back, earlobes and the deltoid region; wounds under tension are at particular risk.
- First-line measures: silicone gel or sheets and pressure garments for prevention and early disease, and intralesional triamcinolone acetonide for established lesions.
- Adjuncts: cryotherapy, 5-fluorouracil, botulinum toxin, pulsed-dye laser, and postoperative radiotherapy after excision in refractory cases.
A ladder from prevention to surgery
Management starts before the scar forms, because established keloids are harder to treat. The steps below move from prevention to surgery combined with adjuvant therapy.
- Prevent in high-risk wounds: minimise tension and close wounds carefully at sites such as the sternum, and avoid elective surgery there when it can be deferred.
- Start silicone early: silicone gel or sheets are applied for several months after the wound has closed, and they are the mainstay of prophylaxis.
- Add pressure: pressure garments are used on the chest and shoulders in burn and wide scars, where they reduce hypertrophic scarring.
- Inject steroid: intralesional triamcinolone acetonide is given into the lesion at intervals, softening and flattening it, and it is the first-line injectable.
- Use adjuncts: cryotherapy, 5-fluorouracil, botulinum toxin and pulsed-dye laser are added for stubborn, itchy or symptomatic lesions.
- Excise and protect: surgical excision is combined with postoperative steroid injections or radiotherapy, because excision alone recurs in many cases.
Where the exam tries to catch you
Keloids and hypertrophic scars are confused because both are raised and thick, but their behaviour and treatment differ.
- Trap: choosing excision alone for a keloid. Correct: recurrence after simple excision is high, so it is combined with steroid, silicone or radiotherapy.
- Trap: calling a red, raised scar that stays within the wound a keloid. Correct: that is a hypertrophic scar, which regresses and responds well to pressure and silicone.
- Trap: assuming darker skin is protected from keloids. Correct: keloids are more common in darker skin types, so early prevention matters most in those patients.
- Trap: relying on topical steroid creams for thick keloids. Correct: intralesional steroids reach the dermis, whereas creams have little effect on established keloid tissue.
Frequently asked questions
What distinguishes a keloid from a hypertrophic scar?
A keloid extends beyond the original wound margin, whereas a hypertrophic scar remains confined to the wound. Hypertrophic scars often flatten over months to a year or two, while keloids usually persist and rarely regress without treatment.
Which intralesional drug is first-line for keloids?
Intralesional triamcinolone acetonide is the first-line injectable treatment for keloids. Repeated injections soften and flatten the lesion, and they are often combined with silicone gel or pressure therapy.
Why is excision alone not recommended for keloids?
Excision alone for keloids carries a high recurrence rate, because the fibroproliferative process can be reactivated at the new wound. Keloid excision is therefore combined with postoperative steroid injections, silicone or radiotherapy in suitable patients.
Which patients are at highest risk of keloid formation?
Keloids are most common in people with darker skin types, in younger patients, especially between 10 and 30 years, and in those with a family history of keloids. Sites such as the sternum, shoulders, earlobes and upper back are also high-risk.
What role does silicone play in keloid management?
Silicone gel or sheets are used for prevention and early management of keloids and hypertrophic scars, applied for several months after wound closure. They are simple, inexpensive and widely used as first-line prophylaxis.